A Glimpse into MetalFlow - Introducing Our 3D-Printed Microfluidic Demo

MetalFlow is our team's project for the Diamond Challenge 2025, an international entrepreneurship competition that empowers high school students to solve real-world problems through innovation.

Our mission is to transform e-waste from toxic trash into a valuable resource. MetalFlow uses microfluidic extraction technology to recover precious metals like gold, lithium, and rare earth elements from discarded electronics, with greater efficiency, less chemical waste, and lower energy consumption than conventional methods.

But because microfluidics operates on a microscopic scale, it's not always easy to explain. That's why we created something you can see and touch.

So I designed a 3D-printed demonstration model to make the MetalFlow extraction process easy to understand, visualize, and explain.

This 3D-printed model illustrates the core function of the MetalFlow microfluidic chip, a system designed to extract valuable metals from e-waste leachate using droplet-based liquid-liquid extraction.

• Leachate In (Top Left, Green): Acidic solution containing dissolved metals from shredded e-waste enters the chip.

• Solvent In (Bottom Left, Yellow): An immiscible organic solvent that contains an extractant, designed to bind to metal ions selectively, is introduced.

• Middle Channel (Reaction Zone): The green and yellow droplets flow in alternating sequence through the chip. As they interact, metal ions transfer from the leachate into the extractant droplets — visually represented by the magnet, symbolizing how metals are "pulled" from one phase into another.

• Extract Out (Bottom Right, Yellow): The extractant, now carrying the recovered metals, exits for further processing (e.g., stripping and recovery).

• Raffinate Out (Top Right, Green): The depleted leachate (raffinate) is separated and exits the system.

• Lever Mechanism (Black): A symbolic representation of the phase separation system that guides droplets into their respective output channels. In practice, this is managed by flow control and sensor monitoring.

  
  

It's a hands-on, visual tool that captures the mechanism behind MetalFlow.

You can find the 3D print model at Makerworld (https://makerworld.com/en/models/1400620-metalflow-flowcell-demo#profileId-1452466). Check it out!

The MetalFlow system can achieve up to 95% metal recovery, with much lower energy use and chemical waste than traditional methods. We hope this model can help others understand the science behind the solution.

Stay tuned for more updates on how I use design thinking to build this model from scratch.